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Monday, August 11 • 11:30 - 12:30
Quantum Hall Effects I

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Invited: Sankar Das Sarma
Topological Qubit in Quantum Hall Systems: Materials Considerations

Possible non-Abelian fractional quantum Hall states, e.g. the 5/2 FQHE, can in principle be used to carry out topologically protected quantum computing operations without any need for quantum error corrections [1]. Although the specific details for creating such a topological qubit in semiconductor quantum Hall systems have been pointed out [2] some years ago, the experimental progress toward developing a topological qubit in the laboratory has been slow. I will discuss in this talk how materials considerations [3] involving the growth and fabrication of high-quality two-dimensional semiconductor systems may play an important role in the eventual realization of the topological quantum computation dream using FQHE qubits.

[1] C. Nayak, S. Simon, A. Stern, M. Freedman, and S. Das Sarma, Rev. Mod. Phys. 80, 1083 (2008).
[2] S. Das Sarma, M. Freedman, and C. Nayak, Phys. Rev. Lett. 94, 166802 (2005).
[3] S. Das Sarma and E. H. Hwang, arXiv 1403.4256 (2014).

Invited: Mohammad Hafezi
Topological Orders in Photonic Systems

Topological features – global properties which are not discernible locally – emerge in a variety of physical systems. Deeper understanding of the role of topology in physics has led to a new class of matter: topologically-ordered systems. The best known examples are quantum Hall effects, where insensitivity to local properties manifests itself as conductance through edge states that is insensitive to defects and disorder.

In this talk, I demonstrate how similar physics can be observed for photons; specifically, how various quantum Hall Hamiltonians can be simulated with photons. I report on the first observation of topological photonic edge states using Silicon-on-insulator technology and discuss their robustness. Furthermore, the addition of optical nonlinearity to the system leads to the possibility of implementing fractional quantum Hall states of photons and anyonic states. In particular, I discuss a scheme to engineer three-body interaction, which is absent in nature, to implement some of the fractional quantum Hall states, in the context of circuit-QED system. Finally, I describe schemes to prepare such many-body states in lossy photonic systems.

Session Chairs

Junichiro Kono

Rice University


Mohammad Hafezi

Assistant Professor, University of Maryland Fellow, Joint Quantum Institute, University of Maryland
Mohammad Hafezi received his diplome d'ingenieur from Ecole Polytechnique (Paris) in 2003 and his Ph.D. from Physics Department at Harvard University in 2009. He moved to the Joint Quantum Institute (NIST/University of Maryland) as a research associate and since 2012 he is a research faculty. His research is at the interface of theoretical quantum optics and condensed matter physics with a focus on fundamental physics and applications in... Read More →

Sankar Das Sarma

Richard E. Prange Chair in Physics, Fellow, Joint Quantum Institute, Director, Condensed Matter Theory Center, University of Maryland
Sankar Das Sarma is an India-born American theoretical condensed matter physicist, who has worked in the areas of strongly correlated materials, graphene, semiconductor physics, low-dimensional systems, topological matter, quantum Hall effect, nanoscience, spintronics, collective properties of ultra-cold atomic and molecular systems, optical lattice, many-body theory, Majorana fermion, and quantum computation. His broad research areas are... Read More →

Monday August 11, 2014 11:30 - 12:30
Room 17A

Attendees (14)